1. Field of the Invention
The present general inventive concept relates to an ink jet head and a method of fabricating the same and more particularly, to an ink jet head having a channel damper and a method of fabricating the same.
2. Description of the Related Art
An ink jet recording device functions to print an image by ejecting fine droplets of print ink to a desired position on a recording medium. Such an ink jet recording device has been widely used since its price is low and numerous color images can be printed at high resolution. The ink jet recording device basically includes an ink jet head for actually ejecting ink, and an ink container in fluid communication with the ink jet head. An ink ejection type of the ink jet recording device is classified into a thermal type using an electro-thermal transducer, and a piezo-electric type using an electromechanical transducer.
The ink jet head used in the thermal type of the ink jet recording device includes a heat-generating resistor provided as the electrothermal transducer, and an ink chamber for temporarily storing the ink to be ejected to the recording medium. The ink chamber is defined to include the heat-generating resistor within its interior using a barrier structure, such as a chamber layer, disposed adjacent to the heat-generating resistor.
A conventional ink jet head having the above barrier structure enclosing three sides of the heat-generating resistor has been disclosed in U.S. Pat. No. 4,794,410, entitled “Barrier Structure for Thermal Ink Jet Print Heads” to Howard H. Taub, et al.
FIG. 1 is a plan view illustrating the barrier structure 3 of the conventional ink jet head disclosed in U.S. Pat. No. 4,794,410.
Referring to FIG. 1, the barrier structure 3 is disposed to enclose three sides of a heat-generating resistor 1. The barrier structure 3 is configured so that three walls are interconnected to each other to enclose the three sides of the heat-generating resistor 1 while a remaining one side of the heat-generating resistor 1 is opened. An ink chamber for containing the heat-generating resistor 1 therein is defined by the barrier structure 3. A portion opened by the barrier structure 3 is provided as an ink channel 5 fluidly communicating with the ink chamber and an ink feed channel (not shown). Ink introduced through the ink feed channel is temporarily stored in the ink chamber through the ink channel 5. The ink stored in the ink chamber is instantly heated by the heat-generating resistor 1 to generate bubbles in the ink. The bubbles increase a pressure in the ink chamber to thereby eject the ink from the ink chamber in a shape of a droplet through a nozzle (not shown). At this time, the ink in the ink chamber is ejected to an exterior through the nozzle, and simultaneously subjected to a back-flow to the ink feed channel through the ink channel 5. The reason for this back-flow phenomenon is that the bubbles generated by the heat-generating resistor 1 are expanded toward the ink feed channel through the ink channel 5. The back-flow phenomenon reduces the pressure required for the ink ejection, thereby decreasing a speed and a straightness of ink droplets ejected from the nozzle. In addition, after the ejection of the ink, a speed of the ink recharged into the ink chamber is also reduced to decrease a frequency of the ink ejection.
The back-flow phenomenon may cause problems in the ink jet head having the barrier structure 3 as shown in FIG. 1. That is, the ink channel 5 fully opens the one side of the heat-generating resistor 1, so that a great deal of the ink back-flows toward the ink feed channel through the ink channel 5 when the ink is ejected. As a result, the speed and the straightness of the ink droplet can be lowered, and the frequency of the ink ejection can be reduced.
To solve the above-mentioned problems, there is a proposal for a method of forming restrictors at both ends of the barrier structure in order to decrease a cross-sectional area of the ink channel. For example, an ink jet head having the restrictor is disclosed in U.S. Pat. No. 4,882,595. Formation of the restrictor permits the back-flow phenomenon of the ink to be decreased, but a recharging speed of the ink into the ink chamber may be reduced due to a reduction of a cross-sectional area of the ink channel.
In conclusion, research on the ink jet head will be continuously required to maximally restrict the expansion of the ink generated by the heat-generating resistor to the exterior of the ink chamber to increase the ejection speed and the straightness of the ink droplet, and simultaneously increase the recharging speed of the ink, so that the frequency of the ink ejection is increased.